1. Field of the Invention
This invention relates to a waterproof automatic weighing apparatus having electrical equipment such as weight sensing elements consisting of load cells or the like, driving sections for opening and closing hopper gates, electromagnetic vibrator sections, and a control unit for controlling the entire apparatus.
2. Description of the Related Art
In an automatic weighing apparatus of this type, some of the components including the dispersion table, the feed troughs, the pool hoppers, the weighing hoppers, the memory hoppers (used as needed) etc. are situated externally due to their necessary attributes, whereas the other components such as the weight sensing elements, the driving sections for opening and closing hopper gates, the electromagnetic vibrator sections, and the control unit having an electrical circuit section are situated internally. In the following, the former group of components will be referred to as external components, and the latter group as internal components.
In an automatic weighing apparatus of this type, articles are fed to the external components, where the cycle of weighing and discharging is repeated. A single automatic weighing apparatus is not always used to weigh one kind of article, but may often be used to weigh different kinds of article, as needed. As a result, it may happen that the remnant of one kind of article is mixed with another kind of article. This is undesirable from the hygienic point of view and also can even cause deterioration in the value of the articles weighed. Even when it is used to weigh only one kind of article, the apparatus is not free from the problem mentioned above since powder, scraps and seasoning such as salt from the articles being weighed will adhere to the external components, which is not only unhygienic but may lead to weighing errors.
Conventionally, these problems have been coped with by washing, whenever necessary, the external components after removing them from the apparatus body, eliminating, at the same time, the above-mentioned adhering matter accumulated on the body. This operation is quite inefficient.
In order to eliminate this inconvenience, various attempts have been made to develop weighing apparatuses which can be washed without removing the external components therefrom. Examples of such apparatuses are proposed in Japanese Utility Model Laid-Open Nos. 59-11816 and 61-160111 as well as Japanese Patent Laid-Open No. 63-282615. These apparatuses are based on an idea according to which internal components are protected by a cover so as to prevent any undesirable effect on them during the washing of the external components. However, what is protected by a cover in these apparatuses is only the electromagnetic vibrator sections, no covering being provided for the other important internal components. Thus, during the washing of the external components, many internal components are left subject to the adhesion of scraps of the articles scattered by washing fluid such as water and air, so that many internal components suffer damage and rust, resulting in deterioration in weighing accuracy and defective operation.